Distributed energy conversion systems

ABSTRACT

A distributed energy conversion system may include one or more DC power sources and two or more inverters to convert DC power from the power sources to AC power. The AC power from the two or more inverters may be combined to provide a single AC output. A module may include one or more photovoltaic cells and two or more inverters. An integrated circuit may include power electronics to convert DC input power to AC output power and processing circuitry to control the power electronics. The AC output power may be synchronized with an AC power distribution system.

CROSS-REFERENCE TO RELATED U.S. PATENT APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 14/988,497, entitled “Distributed Energy ConversionSystems” by Ravindranath Naiknaware et al., which was filed on Jan. 5,2016, and which claims priority to U.S. patent application No.12/340,715, entitled “Distributed Energy Conversion Systems” byRavindranath Naiknaware et al. (now U.S. Pat. No. 9,263,895), which wasfiled on Dec. 20, 2008, and which claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/008,670, entitled“Distributed Energy Conversion Systems” by Ravindranath Naiknaware etal., which was filed on Dec. 21, 2007, the entirety of each of which ishereby incorporated by reference.

BACKGROUND

Power converters are used to convert electric power from one form toanother, for example, to convert direct current (DC) to alternatingcurrent (AC) and vice versa. Power converters play an important role inthe development of alternative energy sources which often provide powerin a form that is not ideal for use or distribution. For example,photovoltaic (PV) panels installed on the roof of a building may providepower in the form of DC current at relatively low voltages. This powermust be converted to AC current at higher voltages for use with lightingor appliances within the building, or for distribution to other usersthrough the power grid. As another example, a plug-in hybrid vehicle mayneed to convert AC power from the grid to DC power for storage in abattery. The DC power from the battery may then need to be convertedback to AC power to operate the vehicle drive train, or to feed powerback to the grid if the vehicle is also used as an off-peak energystorage device. Even within energy systems based on conventionalsources, power converters are becoming more important to implementadvanced energy management, storage and conservation techniques.

FIG. 24 illustrates a prior art photovoltaic (PV) energy system fordelivering solar energy to a utility grid. The PV array is voltage andcurrent sensed to acquire maximum power point tracking at the panel ormodule level. In a solar energy/power conversion system, the inverter isa critical component which controls the flow of electricity between thePV module and the load, for example, a battery or the grid. Conventionalinverters operate at higher power levels, typically from one to severalhundred kilowatts peak (kWp). At these high power levels, inverterstypically require heat sinks and fans or liquid cooling to accommodatehigher heat dissipation. The addition of the fan and/or liquid coolingreduces the reliability of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of an energy converter system accordingto the inventive principles of this patent disclosure.

FIG. 2 illustrates another embodiment of an energy converter systemaccording to the inventive principles of this patent disclosure.

FIG. 3 illustrates another embodiment of an energy converter systemaccording to the inventive principles of this patent disclosure.

FIG. 4 illustrates another embodiment of an energy converter systemaccording to the inventive principles of this patent disclosure.

FIG. 5 illustrates an embodiment of power combining circuitry with ACpower sources in parallel combination according to the inventiveprinciples of this patent disclosure.

FIG. 6 illustrates an embodiment of power combining circuitry with ACpower sources in series combination according to the inventiveprinciples of this patent disclosure.

FIG. 7 illustrates an embodiment of power combining circuitry with DCpower sources in parallel combination according to the inventiveprinciples of this patent disclosure.

FIG. 8 illustrates an embodiment of power combining circuitry with DCpower sources in series combination according to the inventiveprinciples of this patent disclosure.

FIG. 9 illustrates an embodiment of a power converter stack-up with anAC power source according to the inventive principles of this patentdisclosure.

FIG. 10 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure.

FIG. 11 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure.

FIG. 12 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure.

FIG. 13 illustrates an embodiment of a power converter stack-up with aDC power source according to the inventive principles of this patentdisclosure.

FIG. 14 illustrates another embodiment of a power converter stack-upwith a DC power source according to the inventive principles of thispatent disclosure.

FIG. 15 illustrates an embodiment of a power converter stack-up with anenergy storage device according to the inventive principles of thispatent disclosure.

FIG. 16 illustrates another embodiment of a power converter stack-upwith an energy storage device according to the inventive principles ofthis patent disclosure.

FIG. 17 illustrates an embodiment of a power converter stack-up with apower converter and power combiner according to the inventive principlesof this patent disclosure.

FIG. 18 illustrates another embodiment of a power converter stack-upwith a power converter and power combiner according to the inventiveprinciples of this patent disclosure.

FIG. 19 illustrates an embodiment of a power converter stack-up with twopower converters and power combiners according to the inventiveprinciples of this patent disclosure.

FIG. 20 illustrates an embodiment of a power converter stack-up with aDC power source and power combiner according to the inventive principlesof this patent disclosure.

FIG. 21 illustrates an embodiment of a power converter stack-up with apower converter and power combiner according to the inventive principlesof this patent disclosure.

FIG. 22 illustrates an embodiment of a power converter stack-up with anenergy storage device and power combiner according to the inventiveprinciples of this patent disclosure.

FIG. 23 illustrates an embodiment of an inverter system according to theinventive principles of this patent disclosure.

FIG. 24 illustrates a prior art photovoltaic (PV) energy system fordelivering solar energy to a utility grid.

FIG. 25 illustrates an embodiment of a photovoltaic (PV) energy systemaccording to the inventive principles of this patent disclosure.

FIGS. 26-29 illustrate embodiments of integrated power converterarrangements according to the inventive principles of this patentdisclosure.

FIG. 30 illustrates an embodiment of an integrated power converteraccording to the inventive principles of this patent disclosure.

FIG. 31 illustrates an embodiment of a transceiver according to theinventive principles of this patent disclosure.

FIG. 32 illustrates an embodiment of an inverter system according to theinventive principles of this patent disclosure.

FIG. 33 is a schematic diagram of an embodiment of a main power pathsuitable for implementing the inverter system of FIG. 32 according tothe inventive principles of this patent disclosure.

FIG. 34 illustrates an embodiment of a PV panel according to theinventive principles of this patent disclosure.

FIG. 35 illustrates another embodiment of a PV panel according to theinventive principles of this patent disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

This patent disclosure encompasses numerous inventive principlesrelating to energy conversion systems. Such systems include distributedpower converters including power inverters and/or power rectifiers. Suchinverter systems may be used in various applications including but notlimited to solar energy systems, wind power energy systems, thermalenergy systems, various battery systems, fuel cell energy systems,uninterruptible power supplies, hydroelectric energy systems, datacenter systems, communication infrastructure power supplies, electricand hybrid vehicles, household power, motor, satellite, aerospace,consumer applications, etc.

FIG. 1 illustrates an embodiment of an energy converter system accordingto the inventive principles of this patent disclosure. The system ofFIG. 1 includes a DC power source section 10, a first power convertersection 12, an AC power source section 14, a second power convertersection 16 and an energy storage section 18.

The following descriptions relate to the embodiment of FIG. 1, as wellas other embodiments described below. A DC power source may be in theform of rechargeable or non-rechargeable battery, fuel cell, solar cellsat the cell, multi-cell, panel, multi-panel, module, multi-module orgrid level, or any other DC power source thereof, and in any combinationthereof. Solar cells may be photovoltaic cells, includingmonocrystalline, polycrystalline, thin film, etc. An AC power source maybe in the form of an electric grid, consumer electronics, e.g.,uninterruptable power supply (UPS), or any other AC power sourcesthereof, and in any combination thereof. Any AC sources, distributionsystems, components, etc., may be single phase and/or multi-phase in anyconfiguration. Energy storage may be in the form of a rechargeable ornon-rechargeable battery, capacitor, inductor, other charge storagedevice and/or element, or any combination thereof. An AC power combinermay combine sources in series or parallel combination depending forexample on the application of the power converter system. An AC powercombiner may combine the voltages and/or currents and/or frequencyand/or phase of the individual AC sources in any manner, but preferablyin a constructive manner and/or at high efficiency. AC power combiningmay be single phase and/or multi-phase. A DC power combiner may combinesources in series or parallel combination depending for example on theapplication of the power converter system. A DC power combiner maycombine the voltages and/or currents of the individual DC sources in anymanner, but preferably in a constructive manner and/or at highefficiency.

Referring again to FIG. 1, the system may include one or more powercombiners, one or more DC power sources, one or more AC power sourcesand one or more energy storage devices. The energy converter may convertDC power to AC power and vice versa. The energy converter may includeone or more inverters to convert DC power to one or more AC powersources, for example, at high efficiency. The energy converter may alsoconsist of one or more rectifiers to convert AC power to one or more DCpower sources and/or for storage on energy storage devices, for example,at high efficiency. Each DC power combiner and AC power combiner maycombine power in series or parallel combination in any manner,preferably constructively and/or at high efficiency. For DC powercombining, one or more DC power sources and/or energy storage devicesmay be combined in series and/or parallel combination preferably in aconstructive manner. For AC power combining, one or more AC powersources may be combined in series or parallel combination preferably ina constructive manner. AC power combining may be single phase and/ormulti-phase.

Energy may be transferred from one or more DC power sources through oneor more inverters to generate one or more AC sources when power isavailable at the DC power source and/or when energy is required at theAC power sources. For example, DC power from one or more photovoltaiccells may be transferred to one or more AC power grids and/or consumerelectronic devices.

Energy may also be transferred from one or more AC power sources via oneor more rectifiers to one or more DC power sources when power isavailable at the AC power source and/or when energy is required at theDC power sources and/or when energy storage is required. For example,power from one or more AC power grids may be transferred to one or morebatteries and/or capacitors.

The number of DC power sources that may be combined by one or more DCpower combiners may be any number between 1 and H, where H may be anypositive integer. The number of DC power combiners may be any numberbetween 1 and W, where W may be any positive integer. The DC powercombiner may not be required to be part of the energy converter systemdepending, for example, on the application preferably when all the DCsource has known and/or fixed voltage and/or current characteristic.There may be one or more rectifiers and/or inverters connected betweenthe DC power sources and the AC power sources to, for example, convertenergy from DC-AC and vice versa. The number of rectifiers may be anynumber between 0 and J, where J may be any positive integer. The numberof inverters may be any number between 0 and K, where K may be anypositive integer.

The number of AC power sources that may be combined with an AC powercombiner may be any number between 1 and L, where L may be any positiveinteger. The number of AC power combiners between the AC power sourcesand power converters that are connected to DC power sources may be anynumber between 1 and X, where X may be any positive integer. The numberof AC power combiners between the AC power sources and power convertersthat are connected to energy storage devices may be any number between 1and Y, where Y may be any positive integer. The AC power combiners maynot be required to be part of the energy converter system depending, forexample, on the application preferably when all the AC sources haveknown and/or fixed voltage and/or current and/or frequency and/or phasecharacteristics.

There may be one or more rectifiers and/or inverters connected betweenthe AC power sources and the energy storage devices to, for example,convert energy from DC-AC and vice versa. The number of rectifiers maybe any number between 0 and N, where N may be any positive integer. Thenumber of inverters may be any number between 0 and M, where M may beany positive integer. The number of energy storage devices that may becombined with DC power combiners may be any number between 1 and P,where P may be any positive integer.

The number of DC power combiners on the energy storage devices may beany number between 1 and Z, where Z may be any positive integer. The DCpower combiners on the energy storage devices side may not be requiredto be part of the energy converter system depending, for example, on theapplication preferably when all the DC sources have known and/or fixedvoltage and/or current characteristics.

FIG. 2 illustrates an embodiment of another energy converter systemaccording to the inventive principles of this patent disclosure. Thesystem of FIG. 2 includes a DC power source 20, a first power converter22, an AC power source 24, a second power converter 26 and an energystorage device 28. The energy converter may convert DC power to AC powerand vice versa.

The energy converter may include one or more inverters to convert DCpower to one or more AC power sources, for example, at high efficiency.The energy converter may also consist of one or more rectifiers toconvert AC power to one or more DC power sources and/or for storage onenergy storage devices, for example, at high efficiency. Energy may betransferred from one or more DC power sources through one or moreinverters to generate one or more AC sources when power is available atthe DC power sources and/or when energy is required at the AC powersources. For example, DC power from one or more photovoltaic cells maybe transferred to the one or more AC power grids and/or consumerelectronic devices.

Energy may be transferred from one or more AC power sources via one ormore rectifiers to one or more DC power sources when power is availableat the AC power source and/or when energy is required at the DC powersources and/or when energy storage is required. For example, power fromone or more AC power grids may be transferred to one or more batteriesand/or capacitors.

FIG. 3 illustrates an embodiment of another energy converter systemaccording to the inventive principles of this patent disclosure. Thesystem of FIG. 3 includes a DC power source 30, a power converter 32,and an AC power source 34. The energy converter may convert DC power toAC power and vice versa.

The energy converter may consist of one or more inverters to convert DCpower to one or more AC power sources, for example, at high efficiency.The energy converter may also consist of one or more rectifiers toconvert AC power to one or more DC power sources and/or for storage onenergy storage devices, for example, at high efficiency.

Energy may be transferred from one or more DC power sources through oneor more inverters to generate one or more AC sources when power isavailable at the DC power source and/or when energy is required at theAC power sources. For example, DC power from one or more photovoltaiccells may be transferred to the one or more AC power grids and/orconsumer electronic devices.

Energy may be transferred from one or more AC power sources via one ormore rectifiers to one or more DC power sources when power is availableat the AC power source and/or when energy is required at the DC powersources and/or when energy storage is required. For example, power fromone or more AC power grids may be transferred to create one or more DCpower supplies for various applications.

FIG. 4 illustrates an embodiment of another energy converter systemaccording to the inventive principles of this patent disclosure. Thesystem of FIG. 4 includes an AC power source 36, a power converter 38and an energy storage device 40. The energy converter may convert DCpower to AC power and vice versa.

The energy converter may consist of one or more inverters to convert DCpower to one or more AC power sources, for example, at high efficiency.The energy converter may also consist of one or more rectifiers toconvert AC power to one or more DC power sources and/or for storage onenergy storage devices, for example, at high efficiency.

Energy may be transferred from one or more energy storage devicesthrough one or more inverters to generate one or more AC sources whenpower is available at the energy storage devices and/or when energy isrequired at the AC power sources. For example, DC power from one or morebatteries or capacitors may be transferred to the one or more AC powergrids and/or consumer electronic devices.

Energy may be transferred from one or more AC power sources via one ormore rectifiers to one or more DC power sources, when power is availableat the AC power source and/or when energy is required at the DC powersources and/or when energy storage is required. For example, power fromone or more AC power grids may be transferred to one or more batteriesand/or capacitors.

FIG. 5 illustrates an embodiment of power combining circuitry with ACpower sources in parallel combination according to the inventiveprinciples of this patent disclosure. The parallel combination of theindividual AC power sources 42 may be arranged such that the currents ofsome or all of the individual AC power sources may be combined in anyway to provide the combined AC power source 44, but preferably in aconstructive manner. The AC power sources may be phase shifted and/oradjusted so that one or some or all of the AC currents add togetherconstructively. The number of AC power sources that may be combined inparallel combination may be 1 to N, where N is any positive integer.

FIG. 6 illustrates an embodiment of power combining circuitry with ACpower sources in series combination according to the inventiveprinciples of this patent disclosure. The series combination of theindividual AC power sources 46 may be arranged such that the voltages ofsome or all of the individual AC power sources may be combined in anyway to provide the combined AC power source 48, but preferably in aconstructive manner. The AC power sources may be phase shifted and/oradjusted so that one or more or all of the AC voltages add togetherconstructively. The number of AC power sources that may be combined inseries combination may be 1 to N, where N is any positive integer. ACpower combining may be single phase and/or multi-phase.

FIG. 7 illustrates an embodiment of power combining circuitry with DCpower sources in parallel combination according to the inventiveprinciples of this patent disclosure. The parallel combination of theindividual DC power sources 50 may be arranged such that the currents ofsome or all of the individual DC power sources may be combined in anyway to provide the combined DC power source 52, but preferably in aconstructive manner. The number of DC power sources that may be combinedin parallel combination may be 1 to N, where N is any positive integer.

FIG. 8 illustrates an embodiment of power combining circuitry with DCpower sources in series combination according to the inventiveprinciples of this patent disclosure. The series combination of theindividual DC power sources 54 may be arranged such that the voltages ofsome or all of the individual DC power sources may be combined in anyway to provide the combined DC power source 56, but preferably in aconstructive manner. The number of DC power sources that may be combinedin series combination may be 1 to N, where N is any positive integer.

FIG. 9 illustrates an embodiment of a power converter stack-up with anAC power source according to the inventive principles of this patentdisclosure. The embodiment of FIG. 9 includes an AC power source 62, NDC power sources 58 and M energy storage devices 66. The single AC powersource may be connected to one or more DC power sources and/or one ormore energy storage devices. The single AC power source may includepower combining circuitry where AC power may be added, preferably in aconstructive manner. The power combining circuitry may provide aparallel and/or series combination where the AC currents at the outputsof one or more or all of the power converters 60 may be added,preferably in a constructive manner. Also, the AC voltages of one ormore or all AC of the outputs of power converters 64 may be added,preferably in a constructive manner. AC power combining may be singlephase and/or multi-phase.

The number of DC power sources that may be combined in series and/orparallel combination may be 1 to N, where N is any positive integer. Thenumber of energy storage devices that may be combined in series and/orparallel combination may be 1 to M, where M is any positive integer. Nmay be less than, greater than or equal to M.

FIG. 10 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure. The embodiment of FIG. 10 includes an AC power source72, N DC power sources 68 and L energy storage devices 76. The single ACpower source may be connected to one or more DC power sources and/or oneor more energy storage devices. The single AC power source may includepower combining circuitry where AC power may be added, preferably in aconstructive manner. The power combining circuitry may provide aparallel and/or series combination where the AC currents of one or moreor all of the outputs of power converters 70 may be added, preferably ina constructive manner. Also, the AC voltages of one or more or all ofthe outputs of power converters 74 may be added, preferably in aconstructive manner. AC power combining may be single phase and/ormulti-phase.

The number of DC power sources that may be combined in series and/orparallel combination may be 1 to N, where N is any positive integer. Thenumber of power converters on the DC power source side may be 1 to M,where M is any positive integer. The number of power converter on theenergy storage side may be 1 to K, where K is any positive integer. Thenumber of energy storage devices that may be combined in series and/orparallel combination may be 1 to L, where L is any positive integer. Thenumber of DC power sources may be less than, greater than or equal tothe number of power converters they are connected to. The number ofenergy storage devices may be less than, greater than, or equal to thenumber of power converters they are connected to.

FIG. 11 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure. The embodiment of FIG. 11 includes an AC power source82 connected to N DC power sources 78. The AC power source may includepower combining circuitry where AC power may be added, preferably in aconstructive manner. The power combining circuitry may provide aparallel and/or series AC combination where the AC currents of one ormore or all of the outputs of power converters 80 may be added,preferably in a constructive manner.

The number of DC power sources that may be combined in series and/orparallel combination may be 1 to N, where N is any positive integer. Thenumber of power converters may be 1 to M, where M is any positiveinteger. The number of DC power sources may be less than, greater thanor equal to the number of power converters they are connected to.

FIG. 12 illustrates another embodiment of a power converter stack-upwith an AC power source according to the inventive principles of thispatent disclosure. The embodiment of FIG. 12 includes an AC power source84 connected to M energy storage devices 88. The single AC power sourcemay include power combining circuitry where AC power may be added,preferably in a constructive manner. The power combining circuitry mayprovide a parallel and/or series combination where the AC currents ofone or more or all AC currents at the outputs of power converters 86 maybe added, preferably in a constructive manner.

The number of power converters may be 1 to N, where N is any positiveinteger. The number of energy storage devices that may be combined inseries and/or parallel combination may be 1 to M, where M is anypositive integer. The number of energy storage devices may be less than,greater than, or equal to the number of power converters they areconnected to.

FIG. 13 illustrates an embodiment of a power converter stack-up with aDC power source according to the inventive principles of this patentdisclosure. The embodiment of FIG. 13 includes a DC power source 90, N+Kpower converters 92 and 96, M AC power sources 94 and L energy storagedevices 98. The single DC power source may be connected to one or moreof the AC power sources and/or one or more energy storage devices viathe power converters. The single DC power source may include powercombining circuitry where DC power may be added, preferably in aconstructive manner. The power combining circuitry may provide aparallel and/or series combination where the DC currents of one or moreor all of the outputs of power converters 92 may be added, preferably ina constructive manner.

The number of power converters on the DC power source side may be 1 toN, where N is any positive integer. The number of AC power sources maybe 1 to M, where M is any positive integer. The number of powerconverter on the energy storage side may be 1 to K, where K is anypositive integer. The number of energy storage devices that may becombined in series and/or parallel combination may be 1 to L, where L isany positive integer. The number of energy storage devices and/or ACpower sources may be less than, greater than, or equal to the number ofpower converters they are connected to.

FIG. 14 illustrates another embodiment of a power converter stack-upwith a DC power source according to the inventive principles of thispatent disclosure. The embodiment of FIG. 14 includes a DC power source100, N power converters 102 and M AC power sources 104. The single DCpower source may be connected to one or more AC power sources via powerthe converters 102. The single DC power source may include powercombining circuitry where DC power may be added, preferably in aconstructive manner. The power combining circuitry may provide aparallel and/or series combination where the DC currents of one or moreor all outputs of the power converters may be added, preferably in aconstructive manner.

The number of power converters may be 1 to N, where N is any positiveinteger. The number of AC power sources may be 1 to M, where M is anypositive integer. The number of AC power sources may be less than,greater than, or equal to the number of power converters they areconnected to.

FIG. 15 illustrates an embodiment of a power converter stack-up with anenergy storage device according to the inventive principles of thispatent disclosure. The embodiment of FIG. 15 includes an energy storagedevice 114, M+L power converters 108 and 112, N DC power sources 106,and K AC power sources 110. The single energy storage device may beconnected to one or more DC power sources and/or one or more AC powersources via the power converters. The single energy storage device mayinclude power combining circuitry where DC power may be added,preferably in a constructive manner. The power combining circuitry mayprovide a parallel and/or series combination where the DC currents ofone or more or all of the outputs of the power converters may be added,preferably in a constructive manner.

The number of DC power sources may be 1 to N, where N is any positiveinteger. The number of power converters on the DC power source side maybe 1 to M, where M is any positive integer. The number of AC powersources may be 1 to K, where K is any positive integer. The number ofpower converters on the energy storage side may be 1 to L, where L isany positive integer. The number of AC power sources and/or DC powersources may be less than, greater than, or equal to the number of powerconverters they are connected to.

FIG. 16 illustrates another embodiment of a power converter stack-upwith an energy storage device according to the inventive principles ofthis patent disclosure. The embodiment of FIG. 16 includes an energystorage device 120, M power converters 118, and N AC power sources 116.The single energy storage device may be connected to one or more ACpower sources via the power converters. The single energy storage devicemay include power combining circuitry where DC power may be added,preferably in a constructive manner. The power combining circuitry mayprovide a parallel and/or series DC combination where the DC currents ofone or more or all of the outputs of the power converters may be added,preferably in a constructive manner.

The number of AC power sources may be 1 to N, where N is any positiveinteger. The number of power converters may be 1 to M, where M is anypositive integer. The number of AC power sources may be less than,greater than, or equal to the number of power converters they areconnected to.

FIG. 17 illustrates an embodiment of a power converter stack-up with apower converter and power combiner according to the inventive principlesof this patent disclosure. The embodiment of FIG. 17 includes a powerconverter and power combiner 124, energy storage devices 130, powerconverters 128, AC power sources 126 and DC power sources 122. The powerconverter and combiner may be connected to one or more AC power sourcesand/or DC power sources and/or energy storage devices.

The number of DC power sources may be 1 to N, where N may be anypositive integer. The number of AC power sources may be 1 to M, where Mmay be any positive integer. The number of power converters may be 1 toK, where K may be any positive integer. The number of energy storagedevices may be 1 to L, where L is any positive integer.

FIG. 18 illustrates another embodiment of a power converter stack-upwith a power converter and power combiner according to the inventiveprinciples of this patent disclosure. The embodiment of FIG. 18 includesa power converter and power combiner 138, energy storage devices 140,power converters 134, AC power sources 136 and DC power sources 132. Thepower converter and combiner may be connected to one or more AC powersources and/or DC power sources and/or energy storage devices.

The number of DC power sources may be 1 to N, where N may be anypositive integer. The number of power converters may be 1 to M, where Mmay be any positive integer. The number of AC power sources may be 1 toK, where K may be any positive integer. The number of energy storagedevices may be 1 to L, where L is any positive integer.

FIG. 19 illustrates an embodiment of a power converter stack-up with twopower converters and power combiners according to the inventiveprinciples of this patent disclosure. The embodiment of FIG. 19 includesDC power sources 142, a first power converter and power combiner 144, ACpower sources 146, a second power converter and power combiner 148, andenergy storage devices 150. The DC power sources may be connected to thefirst power converter and power combiner. The AC power sources may beconnected between the first and second power converters and powercombiners. The energy storage devices may be connected to the secondpower converter and power combiner.

The number of DC power sources may be 1 to N, where N may be anypositive integer. The number of AC power sources may be 1 to M, where Mmay be any positive integer. The number of energy storage devices may be1 to K, where K is any positive integer.

FIG. 20 illustrates an embodiment of a power converter stack-up with aDC power source and power combiner according to the inventive principlesof this patent disclosure. The embodiment of FIG. 20 includes a DC powersource and power combiner 152 which may be connected to energy storagedevices 156 through power converters 154. The number of power convertersmay be 1 to M, where M may be any positive integer. The number of energystorage devices may be 1 to K, where K is any positive integer.

FIG. 21 illustrates an embodiment of a power converter stack-up with apower converter and power combiner according to the inventive principlesof this patent disclosure. The embodiment of FIG. 21 includes a powerconverter and power combiner 160, DC power sources 158, and energystorage devices 162. The number of DC power sources may be 1 to N, whereN may be any positive integer. The number of energy storage devices maybe 1 to K, where K is any positive integer.

FIG. 22 illustrates an embodiment of a power converter stack-up with anenergy storage device and power combiner according to the inventiveprinciples of this patent disclosure. The embodiment of FIG. 22 includesan energy storage device and power combiner 168 which may be connectedto DC power sources 164 through power converters 166. The number of DCpower sources may be 1 to N, where N may be any positive integer. Thenumber of power converters may be 1 to M, where M is any positiveinteger.

FIG. 23 illustrates an embodiment of an inverter system according to theinventive principles of this patent disclosure. The system of FIG. 23may be designed to convert DC power from any type of DC power source 170to AC power. The AC power inverter may be single phase and/ormulti-phase. It may include one or more power controls 172, one or morepower converters 174, one or more power circuits and/or drivers 176, oneor more filters 178, one or more analog control blocks 180, one or moredigital signal processors (DSPs) 182, one or more sensing circuits 184,one or more analog-to-digital converters (ADCs) 186, one or moredigital-to-analog converters (DACs) 188, one or more multiplexercircuits 190, one or more transceivers 192, one or more energy storagedevices 194, one or more power management blocks 196, and one or moreprotection circuits 198.

The power control block 172 may control the power that flows through theinverter circuits. For example, it may be designed to maximize the powerconversion efficiency of the inverter. It may also be include maximumpower point tracking (MPPT) to assure the inverter is operating at themaximum power available from the DC power source. The power controlblock may also be designed to control power in the inverter in responseto changes in the environment, for example, variations in temperature,and/or pressure, and/or humidity, and/or light illumination, and/oravailability of input DC power. The power control block may also bedesigned to accommodate other operational factors, for example;variations in integration process whether inter-process, intra-processand/or voltage supply.

The power converter 174 may convert one or more DC input voltages and/orcurrents to one or more DC output voltages and/or currents, preferablyat high power conversion efficiency. The power converter may be designedto step-up (i.e. boost) the input DC voltage to a higher output DCvoltage and/or step-down (i.e. buck) the input DC voltage to a loweroutput DC voltage depending on, for example, the specific applicationthe inverter system is intended for. The power converter circuit mayalso be designed to provide both step-up and step-down (i.e.buck-boost/boost-buck) operation and/or to generate multiple output DCvoltages from a single input (e.g. as in a fly-back converter). Theinput voltages to, and output voltages from, the power converter may bea positive or negative signals. The output voltages may be of the samepolarity different polarity relative to the input voltages depending,for example, on the specific application that the inverter system isintended for. The DC power converter circuit may be in the form of alinear and/or a switching regulator. Pulse width modulated signals maybe used to control one or more output voltages of the DC powerconversion, for example, in switching voltage regulators.

The power circuits and/or drivers block (power driver circuit) 176 mayconvert one or more DC voltages and/or currents to one or more ACvoltages and/or currents preferably at high power conversion efficiencyand/or low total harmonic distortion (THD). Passive or active filtersmay be included within the power driver circuit, for example, to reduceharmonic distortion in the DC-AC power conversion. Power switches mayalso be implemented within the power driver circuit, for example, todrive high power AC devices and/or to withstand high output voltages.

The protection circuit 198 may be included to protect the invertersystem and/or protect any or all circuitry connected to the invertersystem. The protect circuitry may limit the voltage, and/or current,and/or temperature of the circuitry it protects from exceeding a certainrange, for example, to protect it from damage. The protection circuitrymay have over-voltage protection capability and/or under-voltageprotection capability to limit the voltage range of the inverter systemand/or the circuitry it is protecting. The protection circuitry may alsohave over-current and/or under-current protection capability to limitthe current range of the inverter system and/or the circuitry it isprotecting. The protection circuitry may also have over-temperatureand/or under-temperature protection capability to limit the currentrange of the inverter system and/or the circuitry it is protecting.

The filter block 178 may include active and/or passive circuitry. Thefilter may be designed to reduce the total harmonic distortion (THD) inthe inverter system. The filter may be low pass, high pass, band passand/or band reject depending, for example, on the intended purpose ofthe filter. The filter may be designed with only passive elements, forexample, resistors and/or capacitors and/or inductors, or the filter mayinclude active components, for example, operational amplifiers (opamps).

Analog control block 180 may be included to provide analog control ofthe power converter and/or driver circuitry, preferably to improve powerconversion efficiency. The analog control may be designed as a feed backloop to the DC-DC power converter and/or DC-AC power driver circuitry,for example, to dynamically control and maximize the power conversionefficiency of these circuit blocks.

Sensing circuitry 184 may be included to sense voltages and/or currentsat any location in the inverter system. The sensing circuit may bedesigned to sense one or more DC voltages and/or currents at, forexample, the DC power source and/or at the output of the DC powerconverter. The sensing circuit may also be designed to sense one or moreAC voltages and/or currents at, for example, the AC power source and/orat the output of the DC-AC power converter and/or power driver circuit.

Energy Storage Device 194 may be in the form of rechargeable ornon-rechargeable battery, inductor, capacitor, other charge storagedevice and/or element, or any combination thereof.

Analog/Digital converter (ADC) 186 may be designed to convert one ormore analog signals of any form to digital signals. The digital signalto the DSP may be sampled with Nyquist sample, oversampling or any othersampling methods, or any combination thereof. Digital/Analog Converter(DAC) 188 may be designed to convert digital signals to analog signalsof any form. The digital signal to the DSP may be sampled with Nyquistsampling, oversampling or any other sampling methods, or any combinationthereof.

Digital signal processor (DSP) 182 may be designed and/or optimized, forexample, for low power operation and/or for high speed operation. TheDSP core may include an internal analog/digital converter to convertanalog signal of any form to digital signals. The DSP core may be, inthe form of application specific integrated circuit (ASIC) and/or fieldprogrammable gate arrays depending, for example, on the specificapplication the inverter system is intended for. The digital signalprocessor may be designed to process digital signals, for example, inthe time domain, and/or frequency domain, and/or spatial domain, and/orwavelet domain and/or autocorrelation domain. The DSP block may consistof random access memory (RAM) that may be read/write or read only memory(ROM) that may be preprogrammed or electrically erasable (i.e. EEPROM).The type of ROM and/or RAM use may be of any type including flash and/ornon-volatile memory. The digital signal to the DSP may be sampled withNyquist sampling, oversampling or any other sampling methods, or anycombination thereof. The DSP may be designed to include one or moredigital filters, for example, finite impulse response (FIR) filtersand/or infinite impulse response (IIR) filters.

The DSP core may be designed to implement maximum power point tracking(MPPT) for the inverter to, for example, assure the inverter isoperating at and/or close to the maximum power. Pulse width modulation(PWM) of signals may be implemented with the DSP core to, for example,implement the control circuitry for the DC-DC power converter. The DSPmay be programmed to act as an active filter for reducing harmonicdistortion, for example, in the power converter from DC-AC. The DSP maybe programmed to control switching of circuitry within the invertersystem, for example, the DC-AC power conversion circuit. The DSP mayalso be programmed to add intelligence to the power control circuit, forexample, to find the maximum power point and/or bypassing of damaged orinefficient DC power sources as part of the inverter system.

Multiplexer 190 may be designed to choose between different digitaland/or analog input sources. The multiplexer circuitry may be designedto select between the different sensing circuitry (for example) voltageand/or current sensing and/or any other digital and/or analog signal.

Transceiver 192 may be design to communicate through circuitry outsideof the inverter for example, through the power line and or wirelesslinks. The transceiver may include a line interface circuit to, forexample, interface the power grid to the transceiver. The transceivermay include one or more low noise amplifiers (LNA) to, for example,amplify the receive signal with low noise figure and/or high gain. Thetransceiver may include automatic gain control (AGC), for example, toautomatically control the gain of the receiver. The transceiver mayinclude driver circuits, for example, to drive the transmitted signalsat high gain and/or efficiency. The transceiver may include a buffercircuit, for example, to amplify the signal to the driver circuitry. Thetransceiver may include on or more filters, for example, to filterunwanted frequency contents, i.e. high frequency noise. The transceivermay include its own ADC and DAC, for example, to convert analog signalsto digital signal and vice versa.

Power management block 196 may be designed to supply a stable DC powersource to the inverter system. Power management may include one or moreswitches or circuitry which controls, monitors and/or analyzes (i) thepower conversion operation of the inverter system and/or componentsthereof (for example, the DC-DC and/or DC-AC power conversion circuitry)(ii) the operating characteristics of the inverter and/or componentsthereof, (iii) the characteristics of the output power of the invertersystem (for example, current, voltage and temporal characteristicsthereof), (iv) the storage operation of one or more of the chargestorage or other energy storage devices and/or charge or energy suppliedthereto (via, for example, the inverter system), and/or (v) thecharacteristics of the output power of one or more of the charge storageor other energy storage devices (for example, current, voltage andtemporal characteristics thereof).

The features described above may be utilized in various combinationsaccording to the inventive principles, and various features may beincluded or omitted in some embodiments depending on the application.For example, power control may be included when maximum power pointtracking (MPPT) is included as part of the system, but may be excluded,for example, when the power coming from the DC power source is fixedand/or when the AC load may be modulated to operate at the peak outputpower. As another example, DC power conversion may not be included aspart of the inverter when DC voltage and/or current is sufficient fordirect conversion to AC voltage and/or current. Filters may not beincluded as part of the inverter system when, for example, the totalharmonic distortion of the inverter system does not need to besuppressed and/or when the number of external components may beminimized to reduce system cost. The analog control block may not beincluded, for example, when feedback from the analog control is notrequired and/or when the DC-DC and DC-AC power converters does not needto be dynamically controlled and/or when power conversion efficiency ofthese circuit blocks does not need to be maximized.

The digital signal processor (DSP) may not be included as part of theinverter system when, for example, digital processing is not required bythe inverter system and/or when the inverter system requirements aresimple to reduce cost and/or when the operation required of the DSP canbe reproduced with other internal and/or external circuitry. The sensingcircuitry may not be included as part of the inverter system when, forexample, no DC and/or AC is needed for maximum power point trackingand/or monitoring of the AC load is not needed. The multiplexercircuitry may not be included as part of the inverter system when, forexample, when multiplexing of analog and/or digital signals is notrequired. The transceiver circuitry may not be included when, forexample, data transmission of any kind is not needed. An energy storagedevice may not be included as part of the inverter system when, forexample, energy storage of any kind is not needed. The power managementfeature may not be included when, for example, power management and/orpower control and/or power conditioning of any kind is not needed.Protection circuitry may not be included as part of the inverter systemwhen, for example, the inverter system has externally connectedprotection circuitry and/or the voltages and/or current and/ortemperature of the protection circuit may be externally controlled.

FIG. 25 illustrates an embodiment of a photovoltaic (PV) energy systemaccording to the inventive principles of this patent disclosure. Thesystem of FIG. 25 may include a PV array of one or more solar cells 202and/or solar panels 202 and/or modules and/or solar grids, one or moreintegrated power converters 206, one or more remote monitoring and/orrecording computers 208, one or more AC distribution panels 210, one ormore power line data interfaces 212, one or more meters 214 and/or ACwiring.

The photovoltaic power conversion may be performed at the cell, and/ormulti-cell, and/or panel, and/or multi-panel, and/or module, and/ormulti-module, and/or grid level.

In some embodiments, an integrated power converter may be fabricatedentirely on a single integrated circuit (IC) (or “chip”), including allpassive components. In other embodiments, it may be preferable to havethe largest passive components such as inductors, transformers andcapacitors located off the IC. In some other embodiments, the integratedpower converter may be fabricated on multiple ICs, for example in amulti-chip module (MCM), in which case various key active or passivecomponents may be located on the same chip or chips as the remainder ofthe semiconductor devices and/or on a separate chip or chips and/oroff-chip, for example, on a common substrate within the package orpackages or outside the package or packages.

An integrated power converter may be designed to, for example, reducethe cost of the solar energy conversion system and/or improve the powerconversion efficiency and/or improve system reliability and/or improvediagnostics and maintenance. By integrating one or more functions of aninverter system on an integrated circuit, an integrated power convertermay be able to implement these functions at more relaxed specifications.

Remote monitoring/recording Computer 208 may record power output of thesolar energy conversion system at, for example, the cell level. It maybe designed to, for example, monitor shading effects of the individualsolar cell and or monitor which solar cell and/or group of solar cellsare not operating and/or inefficiently operating.

AC distribution panel 210 may be designed to divide the main electricallines and/or source into various electrical circuits. The ACdistribution panel may consist of one or more fuses and/or one or morecircuit breakers and/or one or more main switches.

Power line data interface 212 may be designed to communicate across thepower line to the remote monitoring/recording computer. The power linedata interface may consist of a wireless link to communicate with theremote monitoring/recording computer. The power line data interface mayalso be designed to receive critical data.

The system of FIG. 25 may reduce the cost of a solar energy system, forexample, by reducing the number of external components and/or number ofmagnetic components. An integrated power converter implementation may bedesigned to, for example, reduce or eliminate DC wiring and/or cablingissues, and/or reduce or eliminate cable trays or conduits, and/orreduce or eliminate DC fuses and/or connectors. With reduced or no DCwiring, no DC surge protection and/or junction box and/or ground faultdetection and/or protection devices may be required. With no DC wires,DC training and/or certifications are not required for the installationof such a system.

With the inverter functions distributed in an integrated power converterimplementation, the power driving capacity and voltage across eachindividual integrated power converter may be reduced. Reducing the powerdriving and voltage driving specifications of the integrated powerconverter may reduce the cost of the individual integrated powerconverters. Fewer or no blocking diodes may be required at lower powerdrive and/or less or no integration of bypass diodes are required. Atlower voltages across the integrated power converter, the integratedpower converter may be designed in standard high-voltage CMOS processesand may be designed to increase power conversion efficiency of the solarenergy system.

Integration of one or more inverter functions in a high voltage CMOSprocess and/or at lower power may reduce noise in the system and/orimprove electromagnetic interference and/or may improve localizedmaximum power point tracking (MPPT). With the inverter integrated on achip, the assembly process of the solar energy system may be made verysimple to reduce the assembly cost associated with the system. Theindividual inverter may be designed and packaged such that it is easilyintegrated into the solar energy system assembly. The packaging of asolar energy system at the panel and/or module level may be implementedso that additional panels and/or modules may be easily added or removed.The integrated power converter implementation may be designed foradaptive islanding where power in the whole array is not lost and/or forimproved reliability and/or better grid reliability and/or componentreliability due to lower voltage and power scaling. It may also bedesigned to automatically resolve cross circulatory current with naturalload distribution and/or with active harmonic control and/or for easyimplementation of advanced control algorithms.

A distributed inverter system according to the inventive principles ofthis patent disclosure may be designed such that it is optimized forlower system cost, and/or higher system performance, and/or improvedreliability, and/or ease of integration, and/or diagnostics andmaintenance. Diagnostics and/or maintenance may be improved by, forexample, reducing ground fault detection and/or eliminating the need forinverter shelter and/or adding the ability to detect faulty circuitryremotely and/or automatically detect faulty and/or dead inverters.

Compared to conventional inverter systems, a distributed inverter methodaccording to the inventive principles of this patent disclosure may beoptimized for lower system cost, for example, by reducing or eliminatingaltogether the number of external and/or custom off the shelfcomponents, and/or high cost components (for example transformers)and/or DC wiring and/or DC cable trays and/or conduits and/or fusesand/or over current protection circuitry and/or required holders and/orDC connectors, and/or DC surge protection circuitry, and/or junctionboxes, and/or blocking diodes, and/or heavy duty electronics (e.g.transformers).

Other cost saving advantages may be realized since standard AC sidewiring is typically less expensive and/or requires little or nospecialized DC training and certification. Additional cost savings maybe realized because of natural integration and/or replacement of PVmodules and/or bypass diodes and/or adaptation to shadowing of small tolarge size areas of a PV structure and/or reduction in the amount ofequipment to ship and/or handle and/or mount a modular stackable array.

The distributed inverter methods according to the inventive principlesof this patent disclosure may be optimized for higher energy outputand/or increased energy extraction and/or increased power conversionefficiency, for example, by limiting or eliminated the losses due toshadowing in photovoltaic systems. Methods of increasing energyextraction and/or increased power conversion efficiency may include butare not limited to implementation of localized maximum power pointtracking of individual input DC sources.

FIGS. 26-29 illustrate embodiments of integrated power converterarrangements according to the inventive principles of this patentdisclosure. An integrated power converter may be installed at the cell,and/or multi-cell, and/or panel, and/or multi-panel, and/or module,and/or multi-module, and/or grid level.

At the cell level, as shown in FIG. 26, there may be one or moreintegrated power converters 216 per cell 218.

At the multi-cell level, as shown in FIG. 27, there may be one or moreintegrated power converters 220 for each subset 222 of cells. The numberof cells for each subset maybe two or more, however, there may beadditional benefits where the number of cells per subset is a multipleof 2, 4, 6, 8, 9 or 12.

At the panel level, there may be one integrated power converter 224 ateach panel 226 as shown in FIG. 28. Alternatively, there may be multipleintegrated power converters 228 at each panel 230 as shown in FIG. 29.

At the multi-panel level, there may be one or more integrated powerconverters for each subset of panel. The number of panels in the subsetmay be two or more. At the module level, there may be one or moreintegrated power converters for every module. At the multi-module level,there may be one or more integrated power converters for each subset ofmodule. The number of modules in a subset may be two or more. At thegrid level, the number of integrated power converters may be one or morefor every grid.

At the multi-cell, panel, multi-panel, module, multi-module, and gridlevel, the integrated power converters may be placed so that they may,for example, reduce the amount of AC wiring. There may be one or moreintegrated power converters for every single panel. The integrated powerconverters may be located close together, for example, for ease ofintegration or they may be located further apart, for example, each at aparticular solar cell.

In any embodiment, multiple inverters may be located in a singlehousing, in multiple housings, in no housing, etc. In some embodiments,a housing may be a separate component, while in other embodiments, ahousing may be part of some other system component. For example, in theembodiment of FIG. 29, the multiple integrated power converters 228 maybe located in a common housing attached directly to the panel 230, orlocated separately from the panel, e.g., on a rack that holds the panel.Alternatively, the integrated power converters may be located inseparate housings, or smaller groups of the integrated power convertersmay be located in multiple housings, either mounted directly to thepanel, and/or separately from the panel, etc. In yet other embodiments,or more of the integrated power converters may be housed in some othersystem component such as an encapsulant on a panel.

FIG. 30 illustrates an embodiment of an integrated power converteraccording to the inventive principles of this patent disclosure. Thoughshown in the context of a photovoltaic system, the embodiment of FIG. 30may be utilized with any other type of DC power source.

The system of FIG. 30 may include some or all of the followingcomponents: a controller 232, shadow bypass control 234, powerconditioning converter 236, power circuitry and driver 238, passivefilter 240, analog control loop 242, transceiver circuit 244, energystorage conditioning 246, power conditioning 248, power switches 250,voltage reference circuit 252, startup circuit 254, multiplexers 256,sensing circuitry 258, ADC 260, clock generation circuit 262, externalcrystal oscillator 264, and/or energy storage device 266.

The controller 232 may include any type of logic including a digitalsignal processor (DSP), microcontroller, etc., and may be designedand/or optimized, for example, for low power operation and/or for highspeed operation. The controller may implement any or all of thefollowing functionality: maximum power point tracking, active filtering,HD control, power factor control, waveform generation, optimization,switch control, configuration management, shutdown control, startupcontrol, and/or shadow bypass control.

The DSP core may include internal analog/digital converters to convertanalog signal of any forms to digital signals. The DSP core may be inthe form of application specific integrated circuit (ASIC) and/or fieldprogrammable gate arrays depending, for example, on the specificapplication the inverter system is intended for. Digital signalprocessing may be included to process digital signals, for example, inthe time domain, and/or frequency domain, and/or spatial domain, and/orwavelet domain and/or autocorrelation domain. The digital signals to theDSP may be sampled with Nyquist sampling, oversampling or any othersampling methods, or any combination thereof. The DSP may be designed toinclude digital filtering, for example, finite impulse response (FIR)filters and/or infinite impulse response (IIR) filters.

The DSP core may be designed to implement maximum power point tracking(MPPT) for the inverter to, for example, assure the inverter isoperating at and/or close to the maximum power. Pulse width modulation(PWM) of signals may be implemented with the DSP core to, for example,implement the control circuitry for a DC-DC power converter. The DSP maybe programmed to act as an active filter for reducing harmonicdistortion, for example, in the power converter from DC-AC. The DSP maybe programmed to control switching of circuitry within the invertersystem, for example, the DC-AC power conversion circuit. The DSP mayalso be programmed to add intelligence to the power control circuit, forexample, to find the maximum power point and/or bypassing of damaged orinefficient DC power sources as part of the inverter system.

Additional functionality provided by the controller may include HDcontrol, PF control, waveform generation, optimization, configurationmanagement, shutdowns, etc.

Shadow bypass control 234 may be designed to control the power thatflows through the solar energy inverter circuits, for example, whenpower is available from the photovoltaic cells that the block isconnected to. The shadow bypass control circuitry may also be designedso that one or more or all photovoltaic cells connect to it may bedisabled, for example, when the light illumination on the photovoltaiccell or cells is low. The shadow bypass control circuitry may be designfor the bypassing of damaged or inefficient photovoltaic cells as partof a solar energy inverter system. The shadow bypass control block maybe designed such that the power conversion efficiency of the invertermay be maximized.

Maximum power point tracking (MPPT) may be designed as part of theshadow bypass control to, for example, assure the inverter is operatingat maximum power. The shadow bypass control may also be designed tocontrol power in the inverter in response to changes in the environment,for example, variations in temperature, and/or pressure, and/orhumidity, and/or light illumination, and/or availability of input DCpower. The shadow bypass control circuitry may be designed to accountfor other factors, for example, variations in the integration processwhether inter-process or intra-process and/or voltage supply.

Power conditioning converter 236 may be designed to convert a DC voltageto one or more DC voltages preferably at high power conversionefficiency. The power conditioning converter may be designed to step-up(i.e. boost) the input DC voltage to a higher output DC voltage and/orthe power converter may be designed to step-down (i.e. buck) the inputDC voltage to a lower output DC voltage depending on, for example, thespecific application the inverter system is intended for. The powerconditioning converter circuit may also be design to operate for bothstep-up and step-down (i.e. buck-boost/boost-buck) and/or designed togenerate multiple output DC voltages from a single input (e.g., as in afly-back converter). The input DC voltages and output DC voltages to thepower converter may be a positive or negative signals. The output DCvoltages may be of the same or different polarities relative to theinput DC voltages depending, for example, on the specific applicationthat the inverter system is intended for. The DC power conditioningconverter circuit may be in the form of a linear and/or switchingregulator. Pulse width modulated signals may be used to control one ormore output voltages of the DC power conversion, for example, inswitching voltage regulators.

Power circuitry and driver 238 may be designed to convert one or more DCvoltages to one or more AC voltages, preferably at high power conversionefficiency. The power driver circuit may be designed to generate an ACsignal, preferably for example, at high power conversion efficiencyand/or at low total harmonic distortion (THD). Passive or active filtersmay be designed within the power driver circuit, for example, to reduceharmonic distortion in the DC-AC power conversion. Power switches mayalso be implemented within the power driver circuit, for example, todrive high power AC devices and/or to withstand high output voltages.

Filter(s) 240 may be designed to be active or passive. The filter may bedesigned to reduce the total harmonic distortion (THD) in the invertersystem. The filter may be low pass, high pass, band pass or band rejectdepending, for example, on the intended purpose of the filter. Thefilter may be designed with only passive elements, for example,resistors and/or capacitors and/or inductors, or the filter may includeactive components, for example, operational amplifiers.

Analog control loop 242 may be designed to control the power circuit anddriver circuitry. It may be designed to provide analog control of thepower converter and/or driver circuitry, preferably to improve powerconversion efficiency of the inverter system. The analog control loopmay be design as a feed back loop to the DC-DC power converter and/orDC-AC driver circuitry, for example, to dynamically control and maximizethe power conversion efficiency of these circuit blocks. Alternatively,the control loop may be implemented in digital or mixed-signal formseparate from, or integral with, the controller 232.

Transceiver circuit 244 may be designed to, for example, communicatewith the monitoring unit via the power line. The transceiver may bedesigned to, for example, operate at high frequency and low power. Thetransceiver may be design to communicate through circuitry outside ofthe inverter for example, through the power line and/or wireless links.The transceiver may include a line interface circuit to, for exampleinterface the power grid to the transceiver. The transceiver may includeone or more low noise amplifiers (LNA) to, for example, amplify thereceive signal with low noise figure and/or high gain. The transceivermay include automatic gain control (AGC), for example, to automaticallycontrol the gain of the receiver. The transceiver may include drivercircuits, for example, to drive the transmitted signals at high gainand/or efficiency. The transceiver may include a buffer circuit, forexample, to amplify the signal to the driver circuitry. The transceivermay include on or more filters, for example, to filter unwantedfrequency contents, i.e. high frequency noise. The transceiver mayinclude its own ADC and DAC, for example, to convert analog signals todigital signals and vice versa.

Energy storage conditioning 246 may be designed to enable the system tostore energy in the energy storage device.

Power conditioning 248 may include functionality which controls,monitors and/or analyzes (i) the power conversion operation of theinverter system and/or components thereof (for example, the DC-DC and/orDC-AC power conversion circuitry) (ii) the operating characteristics ofthe inverter and/or components thereof, (iii) the characteristics of theoutput power of the inverter system (for example, current, voltage andtemporal characteristics thereof), (iv) the storage operation of one ormore of the energy storage devices and/or energy supplied thereto (via,for example, the inverter system), and/or (v) the characteristics of theoutput power of one or more of the energy storage devices (for example,current, voltage and temporal characteristics thereof).

Power switch block 250 may include one or more power switches totransfer power from the solar cells to the power grid.

Voltage reference circuit 252 may be designed to control the voltagethat is delivered to the power grid and/or the power condition circuit.

Startup circuit 254 may be designed to start up the integrated powerconverter as there is enough solar energy or other energy to power upthe system.

Multiplexer 256 may be designed to choose between different digital oranalog input sources. The multiplexer circuitry may be designed toselect between the different sensing circuitry (for example) voltageand/or current sensing and/or any other digital and/or analog signal.

Sensing circuitry 258A-F may be designed to sense voltages and/orcurrents in the inverter system. The sensing circuit may be designed tosense one or more DC voltages and/or currents at, for example, the DCpower source and/or at the output of the DC power converter. The sensingcircuit may also be designed to sense one or more AC voltages and/orcurrents at, for example, the AC power source and/or at the output ofthe DC-AC power converter and/or power driver circuit.

Clock generation circuit 262 may be designed to generate one or moreclocks for the integrated power converter, particularly for thetransceiver circuit.

Crystal Oscillator 264 may include an internal or external crystaloscillator to generate the input clock to the clock generationcircuitry.

Energy storage block 266 may include one or more energy storage deviceswhich may be designed to store energy from the inverter system. It maybe in the form of rechargeable or non-rechargeable battery, capacitor,other charge storage device and/or element, and/or inductor, or anycombination thereof.

Analog/Digital converter (ADC) 260 may be designed to convert analogsignals of any form to digital signals. The digital signals to the DSPmay be sampled with Nyquist sampling, oversampling, or any othersampling methods, or any combination thereof.

A ground fault interruption (GFI) circuit may be included to provideprotection by detecting and/or shutting down the system in response toground fault conditions, communicating with a remote monitoring station,and/or taking other appropriate actions.

FIG. 31 illustrates an embodiment of a transceiver according to theinventive principles of this patent disclosure. The system of FIG. 31may include some or all of the following: a line interface circuit 268,low noise amplifier 270, automatic gain control 272, driver circuit 274,buffer circuit 276, one or more filters 278, ADC 280, DAC 282, Pre-MAC284, I/0 MUX 286, and/or an interface circuit 288 for a processor.

Line interface circuit 268 may be designed to interface the power gridto the transceiver. Low noise amplifier (LNA) 270 may be designed tooperate with, for example, low noise figure and/or high gain. Automaticgain control (AGC) 272 may be designed to automatically control the gainof the receiver. Driver circuit 274 may be designed to drive thetransmitted signal to the power grid at, for example, high gain and/orefficiency. Buffer circuit 276 may be designed to pre-amplify the signalgoing to the driver circuitry. Filter(s) 278A and B may be designed tofilter out unwanted frequency contents, for example, high frequencynoise. Analog/digital converter 280 may be designed to operate at high,moderate, or low resolution at high, moderate or low speed. It may bedesigned, for example to dissipate low power. Digital/analog converter282 may be designed to operate at high, moderate, or low resolution athigh, moderate or low speed. It may be designed, for example todissipate low power. Pre-MAC and I/O Mux 284 may choose between receivemode and/or transmit mode and/or idle mode. Interface circuit 288 mayinterface the transceiver to any and all types of processors. Theinterface may be serial or parallel or a combination of the two.

FIG. 32 illustrates an embodiment of an inverter system according to theinventive principles of this patent disclosure. DC power is applied tothe system at terminals 292 and 294. The embodiment of FIG. 32 is shownin the context of a solar panel 290, but it may be utilized with otherDC power sources such as fuel cells, batteries, capacitors, etc. In thisexample, the main power path continues through a collection ofcomponents that form a DC-DC converter 306. The DC-DC convertertransforms the DC power from relatively low voltage and high current,which is characteristic of PV panels having crystalline cells and someother DC power sources, to relatively higher voltage and lower currentsuitable for conversion to AC power in a form that can be easilydistributed to a local user and/or transmitted to remote users through apower grid, etc. In other embodiments, for example, systems based onthin-film PV cells, the DC power may be generated at higher voltages,thereby eliminating or reducing the need or usefulness of voltageboosting, pre-regulation, etc. In this embodiment, the DC-DC converteris shown with two stages: a boost-type pre-regulator and a push-pulltype main stage. In other embodiments, however, the DC-DC converter maybe implemented with any suitable arrangement of single or multiplestages.

Referring again to FIG. 32, a zero-ripple input filter 296, for examplea passive filter, may be utilized to reduce high frequency (HF) ripplefor improved efficiency. Depending on the implementation, the benefit ofthe zero ripple filter may not be worth the additional cost.

Pre-regulator 298 may enable the system to operate from a wider range ofinput voltages to accommodate PV panels from different manufacturers.The pre-regulator may also facilitate the implementation of an advancedcontrol loop to reduce input ripple as discussed below. Thepre-regulator may be implemented, for example, as a high-frequency (HF)boost stage with soft switching for high efficiency and compact size. Inthis example, the pre-regulator provides a modest amount of initialvoltage boost to feed the next stage. However, other pre-regulatorstages such as buck converters, buck-boost converters, push-pullconverters, etc., may be used as a pre-regulator stage.

Push-pull stage 300 provides the majority of the voltage boost inconjunction with a transformer 302 and rectifier 304. The use of apush-pull stage may facilitate the implementation of the entire systemwith a single integrated circuit since the drivers for both powerswitches may be referenced to the same common voltage. The output fromthe rectifier stage 304 is applied to a DC link capacitor C_(DC) whichprovides a high voltage DC bus to feed the DC-AC inverter stage 312.

The inverter stage 312 includes a high voltage output bridge 308 which,in this embodiment, is implemented as a simple H-bridge to providesingle-phase AC power, but multi-phase embodiments may also beimplemented. A passive output filter 310 smoothes the waveform of the ACoutput before it is applied to a load or grid at the neutral and lineoutput terminals L and N.

A first (input) PWM controller 314 controls the pre-regulator 296 inresponse to various sense inputs. In the embodiment of FIG. 32, voltagesensors 316 and 320 and current sensor 318 provide a measure of theoverall input voltage and current and the output voltage of thepre-regulator, respectively. However, the first PWM controller mayoperate in response to fewer or more sense inputs. For example, any ofthese sense inputs may be omitted and/or other sense inputs may beincluded, e.g., the voltage on DC link capacitor C_(DC), or currentsmeasured at any other points along the power path.

In one embodiment, the first PWM controller 314 implements an innercontrol loop (shown conceptually by arrow 315) by controlling thepre-regulator 296 to maintain a constant voltage at the input terminals292 and 294. This may reduce or eliminate input ripple, thereby reducingthe size of capacitor C1 and eliminating the zero ripple filter. Inessence, the inner control loop may transfer the energy storage functionfrom the input capacitor C1 to the DC link capacitor C_(DC). This energystorage is used for cycle-by-cycle power balance at the AC outputfrequency. That is, power is preferably drawn from the DC source at aconstant rate, whereas the instantaneous AC power output fluctuatesbetween zero and some maximum value at twice the AC line frequency.

To prevent these AC power fluctuations from being reflected back to theDC power source, a decoupling capacitor is used to store energy duringtroughs (or “valleys”) in the AC line cycle, and release energy duringpeaks in the AC line cycle. This is typically accomplished through theuse of a large electrolytic capacitor for C1. The inner control loop,however, moves this energy storage to the DC link capacitor C_(DC) whereenergy is stored and discharged in the form of large voltagefluctuations on the capacitor. This is in contrast to conventionalsystems in which the DC link voltage is regulated to a constant value.

Regulating a constant DC input voltage may provide several advantages.First, reducing ripple in the input waveform improves the efficiency ofsome DC power sources such as PV panels which suffer from resistivelosses related to the ripple. Second, moving the energy storage to theDC link capacitor may eliminate the need for an input electrolyticcapacitor which is an expensive, bulky and unreliable component with ashort lifespan. Instead, the energy may be stored in a higher voltageform on the DC link capacitor which is less expensive, more reliable,has a longer lifespan and may take up less space. Moreover, the size ofthe DC link capacitor itself may also be reduced.

A maximum power point tracking (MPPT) circuit 344 forms an outer controlloop to maintain the average input voltage and current, sensed byvoltage and current sensors 316 and 318, respectively, at the optimumpoints to maximize the output power available from the DC power source,which in this example, is a PV panel.

A second (push-pull) PWM controller 324 controls the push-pull stage inresponse to the DC link voltage sensed by voltage sensor 326. A DC-linkvoltage controller 322 provides a feedback signal which is compared to areference signal REF and applied to the second PWM controller 324. TheDC-link voltage controller 322 may operate in different modes. In onemode, it may simply convey the instantaneous DC-link voltage to the PWMcircuit, thereby causing the DC-link voltage to be regulated to aconstant value. However, if used in conjunction with the input ripplereduction loop discussed above, the DC-link voltage controller 322 mayfilter out the AC ripple so that the second PWM loop only regulates thelong-term DC value (e.g., the RMS value) of the DC-link voltage. Thatis, the AC ripple on the DC-link capacitor rides on a DC pedestal thatslides up or down in response to the DC-link voltage controller. Thismay be useful, for example, to control distortion in the AC output poweras discussed below.

A third (output) PWM controller 330 controls the four switches in theH-bridge 308 to provide a sinusoidal AC output waveform. A non-DQ,non-cordic polar form digital phase locked loop (DPLL) 332 helpssynchronize the output PWM to the AC power line. The overall AC outputis monitored and controlled by a grid current control loop 336 whichadjusts the third PWM controller 330 in response to outputs from theMPPT circuit, the DC-link voltage controller, the DPLL, and the outputvoltage and/or current. A harmonic distortion mitigation circuit 338further adjusts the output PWM through a summing circuit 334 toeliminate or reduce distortion in response to the output voltage andcurrent waveforms sensed by voltage and current sensors 340 and 342,respectively.

An output signal from the harmonic distortion mitigation circuit 338 mayalso be applied to the DC-link voltage controller for optimization ofthe DC-link voltage. In general, it may be preferable to minimize theDC-link voltage to increase overall efficiency. However, if the troughsof the voltage excursions on the DC-link capacitor fall too low, it maycause excessive distortion in the AC output. Thus, the DC-link voltagecontroller may slide the DC pedestal on the DC-link capacitor up or downto maintain the bottoms of the AC troughs at the lowest point possiblewhile still holding distortion to an acceptable level as indicated bythe harmonic distortion mitigation circuit.

FIG. 33 is a schematic diagram of an embodiment of a main power pathsuitable for implementing the inverter system of FIG. 32 according tothe inventive principles of this patent disclosure. Power from DC powersource 346 is applied to the system at capacitor Cl which may be a largeenergy storage capacitor, or if the input ripple reduction control loopis used, a smaller filter capacitor to prevent HF switching transientsfrom being fed back into the DC power source. Inductor L1, transistor Q1and diode D1 form the pre-regulation boost converter which is controlledby the input PWM controller.

The output from the boost converter appears across capacitor C2 whichmay provide HF filtering and/or energy storage depending on theimplementation. The push-pull stage includes transistors Q2 and Q3 whichalternately drive a split-core transformer T1,T2 in response to thepush-pull PWM controller. The transformer has an appropriate turns ratioto generate a high-voltage DC bus across the DC-link capacitor C_(DC) toadequately feed the output bridge. Depending on the implementation, thetransformer may also provide galvanic isolation between the input andoutput of the inverter system. The rectifier may include passive diodesD2-D5 as shown in FIG. 33, active synchronous rectifiers, or any othersuitable arrangement.

Transistors Q4-Q7 in the HV output bridge are controlled by the outputPWM controller to generate the AC output which is filtered by gridfilter 348 before being applied to the load or power grid.

An advantage of the embodiment of FIG. 33 is that it is readilyadaptable to fabrication as an integrated power converter, for example,with a single integrated circuit (IC). Since most of the power switchesare referenced to a common power supply connection, isolated drivers arenot required for these switches. In a monolithic implementation of theentire structure, there may be dielectric isolation between thehigh-side switches in the output H-bridge and their correspondinglow-side switches. There may also be isolation between differentsections of the system. For example, sense circuitry located in onesection may transfer information to processing circuitry in anothersection that performs control and/or communication and/or otherfunctions in response to the information received from the firstsection. Depending on the particular application and power handlingrequirements, all of the components including the power electronics,passive components, and control circuitry (intelligence) may befabricated directly on the IC chip. In other embodiments, it may bepreferable to have the largest passive components such as inductors,transformers and capacitors located off-chip. In yet other embodiments,the system of FIG. 33 may be implemented as a multi-chip solution.

FIG. 34 illustrates an embodiment of a PV panel according to theinventive principles of this patent disclosure. The panel includes PVcells 350, 352, 354, etc., arranged above a first isolation layer orstratum 356. Each PV cell is coupled to a corresponding one of inverters362, 364, 366, etc., which are fabricated as single integrated powerconverters. In this embodiment, contacts (e.g., bond pads) for the DCinputs Vpv and COM and AC outputs L and N on each inverter chip arearranged on the same side of the inverter. The AC outputs from themultiple inverters are coupled together to form an AC distribution (orcollection) bus between the first isolation layer 356 and a secondisolation layer 358. AC outputs may be single phase and/or multi-phase.An encapsulation layer 360 may be formed over the inverters to provideprotection from environmental elements and/or additional structuralintegrity.

FIG. 35 illustrates another embodiment of a PV panel according to theinventive principles of this patent disclosure. In the embodiment ofFIG. 35, each inverter 374 is connected to a string of PV cells 368,370, 372, etc., rather than individual cells. In this embodiment, onlyone isolation layer 376 separates the PV cells from the inverter orinverters. The terminals for the AC outputs L and N are arranged on theopposite side of the integrated power converter from the DC inputsVp_(PV) and COM. The AC outputs are provided on wire leads 380 and 382which may be combined with the outputs of other inverters on the panel,if any, and/or wired directly to a load or power distribution grid. ACoutputs may be single phase and/or multi-phase. An encapsulation layer378 may be formed over the inverters to provide protection fromenvironmental elements and/or additional structural integrity.

In the embodiments of FIGS. 34 and 35, an additional ground line may beadded to the AC distribution bus depending on the implementation orapplication. The panels of FIGS. 34 and 35 may further include a glasssuperstrate located above the PV cells to provide a rigid structure forthe entire panel. Alternatively, one or both of the isolation layers mayprovide the structural basis for the panel, either rigid or flexible.

FIGS. 34 and 35 provide quasi-exploded cross-sectionals views that arenot to scale or proportion for purposes of illustrating the generalarrangement of components. Spaces shown in the illustrations may notactually be implemented and/or may be filled with encapsulants,insulators, adhesives, etc. The embodiments shown in FIGS. 34 and 35illustrate some possible implementation details of the panels shown inFIGS. 26-29, but neither the panels of FIGS. 26-29, nor the embodimentsshown in FIGS. 34 and 35 are limited to these details.

The inventive principles of this patent disclosure have been describedabove with reference to some specific example embodiments, but theseembodiments can be modified in arrangement and detail without departingfrom the inventive concepts. Such changes and modifications areconsidered to fall within the scope of the following claims.

For example, some of the embodiments described above have beenillustrated in the context of PV solar power systems. However, theinventive principles also apply to systems for other types of DC powersources. Thus, one embodiment of an energy conversion system accordingto the inventive principles includes one or more DC power sources andtwo or more inverters to convert DC power from the power sources to ACpower. In some embodiments, the AC power from the two or more invertersmay be combined to provide a single AC output. For example, the one ormore DC power cells may include one or more fuel cells, one or morephotovoltaic cells, one or more capacitors, e.g., large electrolyticcapacitors, or any combination thereof. In such a system, each of theinverters may be coupled for example to a single one of the DC powercells, or each of the inverters is coupled to a single string of the DCpower cells, etc. The system may be arranged so that the components arepart of a single compact assembly, or physically distributed.

1. (canceled)
 2. A solar photovoltaic system comprising one or moresolar panels, each solar panel comprising: a plurality of strings ofphotovoltaic cells, wherein each string of photovoltaic cells comprisesmultiple individual photovoltaic cells electrically coupled together togenerate a DC power in response to exposure to an amount of sunlight;one or more integrated DC power converters electrically coupled to theplurality of strings of photovoltaic cells, wherein the integrated DCpower converters convert the DC power generated by the photovoltaiccells to a DC output power.
 3. The solar photovoltaic system of claim 2,wherein the integrated DC power converter comprises a plurality ofelectronic components established on a single integrated circuit.
 4. Thesolar photovoltaic system of claim 2, wherein the integrated DC powerconverter comprises a plurality of electronic components established onmultiple integrated circuits.
 5. The solar photovoltaic system of claim2, wherein the integrated DC converters combine the DC power generatedby the photovoltaic cells in a series configuration, a parallelconfiguration or a combination thereof.
 6. The solar photovoltaic systemof claim 2, wherein a single integrated DC converter is electricallycoupled to a single string of the photovoltaic cells.
 7. The solarphotovoltaic system of claim 2, wherein the integrated DC convertercomprises a linear voltage regulator.
 8. The solar photovoltaic systemof claim 2, wherein the integrated DC converter comprises a voltageswitching regulator; and, wherein a pulse width modulated signalcontrols an output voltage of the integrated DC power converter.
 9. Thesolar photovoltaic system of claim 2, wherein the one or more integratedDC power converters are housed by an encapsulant layer of the solarpanel.
 10. The solar photovoltaic system of claim 2, further comprisingat least one DC-to-AC inverter; and, wherein the DC-to-AC invertercomprises a DC input electrically coupled to at least one DC output ofthe integrated DC power converters.
 11. The solar photovoltaic system ofclaim 10, wherein the solar panel comprises a DC-to-AC inverterintegrated with the solar panel.
 12. The solar photovoltaic system ofclaim 11, further comprising an isolation layer separating thephotovoltaic cells from the integrated DC-to-AC inverter.
 13. The solarphotovoltaic system of claim 2, further comprising one or more energystorage devices adapted to store power generated by the plurality ofphotovoltaic cells.
 14. The solar photovoltaic system of claim 2,further comprising shadow bypass control circuitry for bypassing one ormore photovoltaic cells.
 15. A solar panel comprising: one or moresubsets of solar cells, wherein each subset of solar cells comprisesmultiple individual solar cells electrically coupled together togenerate a DC voltage and current in response to exposure to an amountof sunlight; one or more integrated power converters electricallycoupled to each of the subsets of solar cells; and, or more encapsulantlayers housing the subsets of solar cells and the integrated powerconverters.
 16. The solar panel of claim 15, wherein the integratedpower converters convert one or more DC voltages or currents generatedby the subsets of solar cells to one or more DC output voltages orcurrents.
 17. The solar panel of claim 15, wherein the integrated powerconverter comprises a plurality of electrical components established ona single integrated circuit.
 18. The solar panel of claim 15, furthercomprising shadow bypass control circuitry for bypassing one or moresolar cells.
 19. A solar photovoltaic system comprising one or moresolar panels, wherein each solar panel comprises: a plurality ofphotovoltaic cells electrically coupled together to generate a DC powerin response to exposure to an amount of sunlight; one or more integratedpower converters, wherein each integrated power converter iselectrically coupled to one or more of the photovoltaic cells; aplurality of shadow bypass controllers for bypassing one or morephotovoltaic cells, wherein the shadow bypass controllers control the DCpower input to the integrated power converters; and, one or moreencapsulant layers housing the photovoltaic cells, the integrated powerconverters and the shadow bypass controllers.
 20. The solar photovoltaicsystem of claim 19, wherein the integrated power converters convert theDC power generated by the photovoltaic cells to a DC power output. 21.The solar photovoltaic system of claim 19, wherein the integrated powerconverters combine the DC power generated by the photovoltaic cells intoa series configuration, a parallel configuration or a combinationthereof.